CVE-2026-59843

Public on 2026-07-21
Modified on 2026-07-27
Description
A flaw was found in libssh. A remote authenticated peer can advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN, causing later channel writes to loop indefinitely and consume CPU, leading to denial of service.
Severity
Medium severity
Medium
See what this means
CVSS v3 Base Score
6.5
See breakdown

Affected Packages

Platform Package Release Date Advisory Status
Amazon Linux 2023 libssh Not Affected
Amazon Linux 2 - Core libssh2 Not Affected
Amazon Linux 2023 libssh2 Not Affected

CVSS Scores

Score Type Score Vector
Amazon Linux CVSSv3 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

FAQs regarding Amazon Linux ALAS/CVE Severity Red Hat: CVE-2026-59843 Mitre: CVE-2026-59843